The World Health Organization now recommends at least 60 minutes of moderate to vigorous intensity daily physical activity for children ages 5-17. With increased activity recommendations comes increased risk for musculoskeletal injuries. The National Federation of State High School Associations considers the preparticipation physical evaluations (PPE) a prerequisite to athletics participation, yet despite this recommendation there are no large-scale controlled trials confirming the effectiveness of the PPE. The recently updated PPE guidelines promote a functional aspect of testing by incorporating performance based tests designed to evaluate deficits in movement control for identification of increased predisposition for injury. Limitations exist concerning the best recommended functional test components, their ability to predict musculoskeletal injury, and effectiveness as compared to a traditional PPE. As a first step towards addressing this limitation, our preliminary data demonstrates that deficits in functional performance (i.e., balance, strength, and movement control) are able to predict lower extremity injury. To address the gap in the knowledge of the PPE musculoskeletal examination, we will utilize an innovative approach to develop a cost-effective and time- efficient F-PPE for use in clinical settings. We will utilize a national cohortof randomly recruited high schools currently participating in a large-scale prospective longitudinal injury surveillance study (High School Reporting Injuries Online-RIO project). By using our High School RIO injury surveillance system we will record injury occurrence on athletes from 20 high schools for one year to identify which F-PPE measurement(s) are best associated with injury risk and develop operational procedures for the F-PPE. Our primary hypothesis is that functional pre-participation physical evaluations (F-PPE) will better predict lower extremity injury than traditional musculoskeletal PPE. Aim 1 hypothesis is that asymmetry indices will provide improved positive predictive value during a standardized F-PPE operational procedure developed to predict lower extremity injury risk for individuals participating in organized high school sponsored athletics. Aim 2 will utilize the F-PPE operational procedure developed in Aim 1 for four consecutive years to establish the prediction capabilities of the F-PPE. Aim 2 hypothesis is that injury risk prediction performance of the F-PPE will provide increased predictive capabilities as compared to the traditional PPE musculoskeletal examination model for assessing lower extremity injury risk in high school-aged athletic participants. The proposed research is significant because it will help to understand the parameters of functional performance testing in the PPE and evaluate methods for improving risk prediction of musculoskeletal lower extremity injury.